Powertrain, generic (extended)

P2BDD Motor Electronics Coolant Temperature Sensor C Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P2BDD is the plausibility check of coolant temperature sensor C: electrically the signal looks fine, but the reported value cannot be right when set against other temperatures. No manufacturer documents P2BDD publicly. Two published approaches show how such a check can run while driving instead of after a cold soak. GM's 2011 Volt compares its electronics coolant sensor with the high-voltage charger temperature and flags a gap above 38 °C while the inverter module requests pump operation, or 40 °C otherwise, in 32 of 40 samples at 250 ms, Type B. A Nissan patent compares the inverter power element temperature with the coolant reading and applies a tighter limit when the element appears colder than the water, which physics rules out. Hard faults of sensor C are P2BDE and P2BDF.

Likely causes

Sensor C reading drifted away from the true coolant temperature
Air or weak flow at the sensor C location, so it sees a local hot or cold spot
Corroded terminals adding resistance in the sensor C circuit
Faulty comparison temperature from another sensor in the system

Symptoms

  • Check engine light without an obvious drivability problem
  • Cooling fan behaviour that does not match the conditions
  • Power or charging limitation under heavy load

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€60–500
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

motor electronics coolant temp sensor cwiring harnesshybrid control module

Related codes

P2BDCP2BDEP2BDFP2BD9P0CEF

References: gsi.ext.gm.com, patents.google.com, law.cornell.edu.